Changes in haematocrit values in blood samples treated with and without oxygen: a comparative study with four salmonid species

Changes in haematocrit values under lowered oxygen tension and aerobically treated blood samples of rainbow trout Salmo gairdneri (Richardson), landlocked Baltic salmon S. salar (L.), brown trout S. trutta lacustris (L.) and lake trout Salvelinus namaycush (Walbaum) have been studied in vitro . The mean haematocrit value increased during 2 h incubation under lowered oxygen tension by 32.7 ± 3.1% in rainbow trout, 28.2 ± 2.8% in landlocked Baltic salmon, 29.2 ± 5.6% in brown trout and 25.2 ± 2.8% in lake trout. During corresponding incubation with oxygen the mean haematocrit value decreased below the starting level by 18.1 ± 1.9% in rainbow trout, 18.3 ± 4.8% in landlocked Baltic salmon, 22.4 ± 0.7% in brown trout and 11.8 ± 1.7% in lake trout. Consequently, the changes in the haematocrit values were greater in the species belonging to the genus Salmo than in that of the genus Salvelinus . The increase in the haematocrit values seems to have resulted from swelling of the erythrocytes and their decrease is similarly attributable to shrinking of the cells. The reasons for this swelling, which may be complicated, and its apparent significance for haematocrit determinations are discussed.     

CuZn superoxide dismutase, Mn superoxide dismutase, catalase and glutathione peroxidase in glutathione-deficient human fibroblasts

The effect of genetically determined glutathione deficiency on the fibroblast content of CuZn superoxide dismutase, Mn superoxide dismutase, catalase and glutathione peroxidase was investigated. No significant differences between glutathione-deficient and -proficient human fibroblasts were revealed. There was a large variation in the content of the investigated enzymes in fibroblasts grown and analysed on different occasions. Whereas the contents of CuZn superoxide dismutase, catalase and glutathione peroxidase did not deviate much from what has been found in other human cell-lines and tissues, the fibroblasts were found to contain exceptional amounts of Mn superoxide dismutase.     

A technique for repeated sampling of the blood of individual resting fish.

A dorsal cannulation technique is described. It has been employed for repeated blood sampling in unanaesthetized rainbow trout (Salmo gairdneri) kept singly in special receptacles described in the paper. The level of the studied haematological parameters (Haematocrit, Hb, glucose, lactate, K+, Na+, Ca2+) differed between fish kept in receptacles for 1 week and free-swimming fish, most probably owing to differences in the motility of the fish. The receptacle seems to minimize visual and handling disturbances, and permits both the standardization of experimental conditions and quick and easy sampling via the dorsal aorta cannula. The general variation in the blood parameter values was very small compared with the previously reported variation in such values for rainbow trout.     

Extracellular Histones Induce Chemokine Production in Whole Blood Ex Vivo and Leukocyte Recruitment In Vivo

The innate immune system relies to a great deal on the interaction of pattern recognition receptors with pathogen- or damage-associated molecular pattern molecules. Extracellular histones belong to the latter group and their release has been described to contribute to the induction of systemic inflammatory reactions. However, little is known about their functions in the early immune response to an invading pathogen. Here we show that extracellular histones specifically target monocytes in human blood and this evokes the mobilization of the chemotactic chemokines CXCL9 and CXCL10 from these cells. The chemokine induction involves the toll-like receptor 4/myeloid differentiation factor 2 complex on monocytes, and is under the control of interferon-γ. Consequently, subcutaneous challenge with extracellular histones results in elevated levels of CXCL10 in a murine air pouch model and an influx of leukocytes to the site of injection in a TLR4 dependent manner. When analyzing tissue biopsies from patients with necrotizing fasciitis caused by Streptococcus pyogenes, extracellular histone H4 and CXCL10 are immunostained in necrotic, but not healthy tissue. Collectively, these results show for the first time that extracellular histones have an important function as chemoattractants as their local release triggers the recruitment of immune cells to the site of infection.     

A novel C3 mutation causing increased formation of the C3 convertase in familial atypical hemolytic uremic syndrome

Atypical hemolytic uremic syndrome has been associated with dysregulation of the alternative complement pathway. In this study, a novel heterozygous C3 mutation was identified in a factor B-binding region in exon 41, V1636A (4973 T > C). The mutation was found in three family members affected with late-onset atypical hemolytic uremic syndrome and symptoms of glomerulonephritis. All three patients exhibited increased complement activation detected by decreased C3 levels and glomerular C3 deposits. Platelets from two of the patients had C3 and C9 deposits on the cell surface. Patient sera exhibited more C3 cleavage and higher levels of C3a. The C3 mutation resulted in increased C3 binding to factor B and increased net formation of the C3 convertase, even after decay induced by decay-accelerating factor and factor H, as assayed by surface plasmon resonance. Patient sera incubated with washed human platelets induced more C3 and C9 deposition on the cell surface in comparison with normal sera. More C3a was released into serum over time when washed platelets were exposed to patient sera. Results regarding C3 and C9 deposition on washed platelets were confirmed using purified patient C3 in C3-depleted serum. The results indicated enhanced convertase formation leading to increased complement activation on cell surfaces. Previously described C3 mutations showed loss of function with regard to C3 binding to complement regulators. To our knowledge, this study presents the first known C3 mutation inducing increased formation of the C3 convertase, thus explaining enhanced activation of the alternative pathway of complement.     

Groove-binding unsymmetrical cyanine dyes for staining of DNA: dissociation rates in free solution and electrophoresis gels

The rates of dissociation of three non-intercalative unsymmetrical cyanine dyes, BEBO, BETO and BOXTO from mixed-sequence DNA have been studied with the DNA either free in solution or in confining porous agarose gels. The properties of the new dyes were compared to the related intercalating dyes BO, BO-PRO, TO-PRO and YO-PRO. With DNA in solution, BEBO dissociates more slowly than the monovalent BO and interestingly also more slowly than the divalent dye BO-PRO. Similarly, both BETO and BOXTO exhibit considerably slower dissociation than TO-PRO. The new dyes show biexponential dissociation kinetics in mixed-sequence DNA. The average rate of dissociation increases with increasing ionic strength, but the salt dependence of the dissociation is weaker than for the corresponding intercalating dye. The rate of dye-dissociation decreases by a factor of about 10⁵ in the gel. The rates for the dyes generally follow the pattern that we observe with the DNA in free solution, however a more accentuated stabilization was seen for intercalators than for groove-bound dyes. The results show that, in particular, BOXTO is a promising candidate as a preferentially groove-bound DNA-stain with a large enhancement of the fluorescence quantum yield upon binding to DNA, and which exhibits slow and salt-insensitive dissociation compared to corresponding intercalative dyes.     

Spinal cord evoked potentials and edema in the pathophysiology of rat spinal cord injury

Summary The possibility that nitric oxide is somehow involved in the early bioelectrical disturbances following spinal cord injury in relation to the later pathophysiology of the spinal cord was examined in a rat model of spinal cord trauma. A focal trauma to the rat spinal cord was produced by an incision of the right dorsal horn of the T 10–11 segments under urethane anaesthesia. The spinal cord evoked potentials (SCEP) were recorded using epidural electrodes placed over the T9 and T12 segments of the cord following supramaximal stimulation of the right tibial and sural nerves in the hind leg. Trauma to the spinal cord significantly attenuated the SCEP amplitude (about 60%) immediately after injury which persisted up to 1h. However, a significant increase in SCEP latency was seen at the end of 5h after trauma. These spinal cord segments exhibited profound upregulation of neuronal nitric oxide synthase (NOS) immunoreactivity, and the development of edema and cell injury. Pretreatment with a serotonin synthesis inhibitor drug p-chlorophenylalanine (p-CPA) or an anxiolytic drug diazepam significantly attenuated the decrease in SCEP amplitude, upregulation of NOS, edema and cell injury. On the other hand, no significant reduction in SCEP amplitude, NOS immunolabelling, edema or cell changes were seen after injury in rats pretreated with L-NAME. These observations suggest that nitric oxide is somehow involved in the early disturbances of SCEP and contribute to the later pathophysiology of spinal cord injury.     

Robert H. Whittaker (1920–1980): The man and his work

R. H. Whittaker enlivened many fields within ecology, systematics and evolution with his insights. Perhaps his most significant contributions to ecology lie in the development of the theories and methods of gradient analysis. Through the verification of the individualistic hypothesis with field data from many regions, and the subsequent development and dissemination of methods for studying species distributions along continua, he helped replace the Clementsian paradigm with a Gleasonian one. His extensive field data on primary production, nutrient cycling patterns and species diversity established new standards for documentation in synecology and helped clarify the basis for site-to-site variation in these variables. Through his broad command of the ecological literature, his writings and his contact with ecologists throughout the world he fostered international understanding of the diversity of approaches to vegetation study.